Patent Law Practice Center

Rader: Vitiation Can’t Swallow Doctrine of Equivalents

Last week, on December 4, 2012, the Federal Circuit addressed the doctrine of equivalents and reminded district courts not to employ “vitiation” to nullify the doctrine of equivalents. The case was Deere & Co. v. Bush Hog, LLC.  At trial in the United States District Court for the Southern District of Iowa, the district court construed the terms of Deere’s U.S. Patent No. 6,052,980 and granted the defendants Bush Hog and Great Plains Manufacturing, Inc.’s summary judgment of noninfringement.

On appeal to the Federal Circuit, Chief Judge Rader (writing for the majority and joined by Judge Newman and Judge Plager) affirmed the construction of the claim term “rotary cutter deck” and the determination that the terms “substantially planar” and “easily washed off” do not render the asserted claims invalid under 35 U.S.C. § 112. However, the Federal Circuit also determined that because the district erroneously construed the term “into engagement with” to require direct contact, that construction was reversed.  Accordingly, the grant of summary judgment was also reversed and the case remanded for further proceedings consistent with the Federal Circuit decision.

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